Process cartridge with mounting projections and image forming apparatus using such a process cartridge

Abstract

A process cartridge detachably mountable to a main assembly of an electro-photographic image forming apparatus including a cartridge frame; an electro-photographic photosensitive drum; processing device actable on the electro-photographic photosensitive drum; a first projection projecting outward from one of opposite ends of the cartridge frame, coaxial with the electro-photographic photosensitive drum; a second projection projecting outward from the other of the opposite ends of the cartridge frame, coaxial with the electro-photographic photosensitive drum; wherein the first and second projections are different in size.

What is claimed is: 
     
       1. A process cartridge detachably mountable to a main assembly of an electro-photographic image forming apparatus, said process cartridge comprising: a cartridge frame;   an electro-photographic photosensitive drum;   processing means for acting on said electro-photographic photosensitive drum;   a first projection projecting outwardly from one of opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum; and   a second projection projecting outwardly from the other of said opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum,   wherein said first projection and said second projection are cylindrical, and a diameter of said second projection is larger than a diameter of said first projection.   
     
     
       2. A process cartridge according to claim 1, wherein a thickness of a cylindrical wall of said second projection is greater than a thickness of a cylindrical wall of said first projection. 
     
     
       3. A process cartridge according to claim 1 or 2, wherein one end of a first drum shaft, for supporting said electro-photographic photosensitive drum, is pressed into a central portion of said first projection, and one end of a second drum shaft, for supporting said electro-photographic photosensitive drum, is pressed into a central portion of said second projection, and wherein said second drum shaft is larger in diameter than said first drum shaft. 
     
     
       4. A process cartridge according to claim 1, wherein a drum gear is mounted at one end of said electro-photographic photosensitive drum, and wherein, when said process cartridge is mounted to the main assembly of the electro-photographic image forming apparatus, said drum gear meshes with a driving gear provided in the main assembly to receive a driving force for rotating said electro-photographic photosensitive drum. 
     
     
       5. A process cartridge according to claim 4, wherein said drum gear is a compound gear, a first gear portion of which meshes with the driving gear when said process cartridge is mounted to the main assembly of the electro-photographic image forming apparatus, and a second gear portion of which meshes with a transfer roller gear provided in the main assembly of the electro-photographic image forming apparatus to transmit a driving force to the transfer roller for rotating the transfer roller. 
     
     
       6. A process cartridge according to claim 1, wherein, when said process cartridge is mounted to the electro-photographic image forming apparatus, said first projection and said second projection are engaged with recesses provided in the main assembly to position said process cartridge, wherein the main assembly is provided with a first guide portion for guiding said first projection to the recess, and a second guide portion for guiding said second projection to the recess, and wherein an opening of the second guide portion, through which said second projection is to be put, is larger than an opening of the first guide portion, through which said first projection is to be put, thereby preventing said second projection from being put through the opening of the first guide portion. 
     
     
       7. A process cartridge according to claim 1, wherein said process cartridge integrally comprises said electro-photographic photosensitive drum, charging means or developing and cleaning means, as said processing means, and is detachably mountable to the main assembly of the electro-photographic image forming apparatus. 
     
     
       8. A process cartridge according to claim 1, wherein said process cartridge integrally comprises said electro-photographic photosensitive drum, and at least one of charging means, developing means, and cleaning means, as said processing means, and is detachably mountable to the main assembly of the electro-photographic image forming apparatus. 
     
     
       9. A process cartridge according to claim 1, wherein said process cartridge integrally comprises said electro-photographic photosensitive drum and charging means as said processing means, and is removably mountable in the main assembly of the electro-photographic image forming apparatus. 
     
     
       10. An electro-photographic image forming apparatus, for forming an image on a recording material, usable with a detachably mountable process cartridge, said apparatus comprising: a. mounting means for detachably mounting a process cartridge that includes:   a cartridge frame;   an electro-photographic photosensitive drum;   processing means for acting on said electro-photographic photosensitive drum;   a first projection projecting outwardly from one of opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum; and   a second projection projecting outwardly from the other of the opposite ends of said cartridge frame, and coaxial with said electro-photographic photosensitive drum,   wherein said first and second projections are cylindrical, and a diameter of said second projection is larger than a diameter of said first projection;   b. fixing means for fixing on a recording material a toner image, which is formed on said electro-photographic photosensitive drum contained in said process cartridge mounted in said mounting means, and which is transferred onto the recording material; and   c. conveying means for conveying the recording material;   wherein said mounting means comprises a first guide portion for guiding said first projection, and a second guide portion for guiding said second projection, and wherein a second projection insertion opening of said second guide portion is larger than a first projection insertion opening of said first guide portion.   
     
     
       11. An electro-photographic image forming apparatus according to claim 10, wherein said electro-photographic image forming apparatus is an electro-photographic copying machine, a laser beam printer, or a facsimile apparatus. 
     
     
       12. A process cartridge detachably mountable to a main assembly of an electro-photographic image forming apparatus, said process cartridge comprising: a cartridge frame;   an electro-photographic photosensitive drum;   processing means for acting on said electro-photographic photosensitive drum;   a first cylindrical projection projecting outwardly from one of opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum;   a second cylindrical projection projecting outwardly from the other of the opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum, said first cylindrical projection having a diameter that is smaller than a diameter of said second cylindrical projection;   a drum gear, which is provided at one axial end of said electro-photographic photosensitive drum, and meshes with a driving gear provided in the main assembly to receive a driving force for rotating said electro-photographic photosensitive drum when said process cartridge is mounted in the main assembly of the electro-photographic image forming apparatus;   a first drum shaft, which is pressed into a central portion of said first cylindrical projection, and which supports said electro-photographic photosensitive drum on said cartridge frame; and   a second drum shaft, which is pressed into a central portion of said second cylindrical projection, and which supports said electro-photographic photosensitive drum on said cartridge frame,   wherein said second cylindrical projection is larger than said first cylindrical projection, wherein a thickness of said second cylindrical projection is greater than a thickness of said first cylindrical projection, and wherein said second drum shaft is larger in diameter than said first drum shaft.   
     
     
       13. A process cartridge according to claim 12, wherein one end of said first drum shaft is pressed into a central portion of said first cylindrical projection, and one end of said second drum shaft is pressed into a central portion of said second cylindrical projection. 
     
     
       14. A process cartridge according to claim 12, wherein said drum gear is a compound gear, a first gear portion of which meshes with said driving gear when the process cartridge is mounted to the main assembly of the electro-photographic image forming apparatus, and a second gear portion of which meshes with a transfer roller gear provided on the main assembly of the electro-photographic image forming apparatus to transmit a driving force to said transfer roller for rotating said transfer roller. 
     
     
       15. A process cartridge according to claim 12 or 14, wherein, when the process cartridge is mounted to the electro-photographic image forming apparatus, said first cylindrical projection and said second cylindrical projection are engaged with recesses provided in the main assembly to position the process cartridge, wherein said main assembly is provided with a first guide portion for guiding said first projection to the recess, and a second guide portion for guiding said second projection to the recess, and wherein an opening of the second guide portion, through which the second projection is to be put, is larger than an opening of the first guide portion, through which the first projection is to be put, thereby preventing said second projection from being put through the opening of the first guide portion. 
     
     
       16. A process cartridge according to claim 12, wherein said process cartridge comprises said electro-photographic photosensitive drum, charging means or developing means and cleaning means, as said processing means, and is detachably mountable to the main assembly of the electro-photographic image forming apparatus. 
     
     
       17. A process cartridge according to claim 12, wherein said process cartridge integrally comprises said electro-photographic photosensitive drum, and at least one of charging means, developing means, and cleaning means, as said processing means, and is detachably mountable to the main assembly of the electro-photographic image forming apparatus. 
     
     
       18. A process cartridge according to claim 12, wherein said process cartridge integrally comprises said electro-photographic photosensitive drum and charging means as said processing means, and is detachably mountable to the main assembly of the electro-photographic image forming apparatus. 
     
     
       19. A process cartridge according to claim 12, wherein said first cylindrical projection and said second cylindrical projection are one of entirely cylindrical and partially cylindrical. 
     
     
       20. An electro-photographic image forming apparatus, for forming an image on a recording material, to which a process cartridge is detachably mountable, said apparatus comprising: a. mounting means for removably mounting a process cartridge that includes: a cartridge frame;   an electro-photographic photosensitive drum;   processing means for acting on said electro-photographic photosensitive drum;   a first cylindrical projection projecting outwardly from one of opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum;   a second cylindrical projection projecting outwardly from the other of the opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum, said first cylindrical projection having a diameter that is smaller than a diameter of said second cylindrical projection;   a drum gear, which is provided at one end of said electro-photographic photosensitive drum, and meshes with a driving gear provided in a main assembly of said electro-photographic image forming apparatus to receive a driving force for rotating said electro-photographic photosensitive drum when said process cartridge is mounted in the main assembly of the electro-photographic image forming apparatus;   a first drum shaft, which is pressed into a central portion of said first cylindrical projection, and supports said electro-photographic photosensitive drum on said cartridge frame; and   a second drum shaft, which is pressed into a central portion of said second cylindrical projection, and which supports said electro-photographic photosensitive drum on said cartridge frame;     b. transferring means for transferring onto the recording material a toner image formed on said electro-photographic photosensitive drum contained in said process cartridge mounted in said mounting means;   c. fixing means for fixing to the recording material a toner image, which is transferred onto the recording material by said transferring means; and   d. conveying means for conveying the recording material; wherein said second cylindrical projection is larger than said first cylindrical projection; a thickness of said second cylindrical projection is greater than a thickness of said first cylindrical projection; and said second drum shaft is larger in diameter than said first drum shaft;   wherein said mounting means comprises a first guide portion for guiding said first cylindrical projection, and a second guide portion for guiding said second cylindrical projection; and   wherein a second projection insertion opening of said second guide portion is larger than a first projection insertion opening of said first guide portion.     
     
     
       21. An electro-photographic image forming apparatus according to claim 20, wherein said electro-photographic image forming apparatus is an electro-photographic copying machine, a laser beam printer, or a facsimile apparatus. 
     
     
       22. A process cartridge detachably mountable to a main assembly of an electro-photographic image forming apparatus, wherein the main assembly is provided with a first guiding portion and a second guiding portion, and the second guiding portion has an insertion opening which is larger than that of the first guiding portion, said process cartridge comprising: a cartridge frame;   an electro-photographic photosensitive drum;   a charge roller for charging said electro-photographic photosensitive drum;   a development roller for developing a latent image formed on said electro-photographic photosensitive drum, rotatable to convey toner to said electro-photographic photosensitive drum;   a cleaning blade in contact with said electro-photographic photosensitive drum to remove toner remaining on said electro-photographic photosensitive drum;   a first cylindrical projection, which projects outwardly from one of opposite ends of said cartridge frame, coaxially with said electro-photographic photosensitive drum, and is guided by said first guide portion;   a second cylindrical projection, which projects outwardly from the other of the opposite ends of said cartridge frame, coaxially with said electro-photographic photosensitive drum, and is guided by said second guide portion;   a drum gear, which is provided at one end of said electro-photographic photosensitive drum, and which meshes with a driving gear provided on the main assembly to receive a driving force for rotating said electro-photographic photosensitive drum when said process cartridge is mounted to the main assembly of the electro-photographic image forming apparatus;   a first drum shaft, which is pressed into a central portion of said first cylindrical projection, and which supports said electro-photographic photosensitive drum on said cartridge frame; and   a second drum shaft, which is pressed into a central portion of said second cylindrical projection, and which supports said electro-photographic photosensitive drum on said cartridge frame;   wherein said second cylindrical projection is larger than an opening of said first guide portion, thereby being prevented from being inserted into the opening of said first guide portion;   wherein a diameter of said second cylindrical projection is larger than a diameter of said first cylindrical projection;   wherein a thickness of said second cylindrical projection is greater than a thickness of said first cylindrical projection; and   wherein said second drum shaft is larger in diameter than said first drum shaft.   
     
     
       23. A process cartridge according to claim 22, wherein said drum gear is a compound gear, a first gear portion of which meshes with said driving gear when the process cartridge is mounted to the main assembly of the electro-photographic image forming apparatus, and a second gear portion of which meshes with a transfer roller gear provided in the main assembly of the electro-photographic image forming apparatus to transmit the driving force for rotating said transfer roller. 
     
     
       24. A process cartridge according to claim 22, wherein, when the process cartridge is mounted in the electro-photographic image forming apparatus, said first cylindrical projection and said second cylindrical projection are engaged with recesses provided in the main assembly to position the process cartridge, one recess being provided in said first guide portion, and another recess being provided in said second guide portion. 
     
     
       25. A process cartridge according to claim 22, wherein said process cartridge integrally comprises said electro-photographic photosensitive drum, charging means or developing means and cleaning means, as said processing means, and is detachably mountable to the main assembly of the electro-photographic image forming apparatus. 
     
     
       26. A process cartridge according to claim 22, wherein said first cylindrical projection and said second cylindrical projection are one of entirely cylindrical and partially cylindrical. 
     
     
       27. An electro-photographic image forming apparatus, for forming images on a recording material, to which a process cartridge is detachably mountable, said apparatus comprising: a. a first guide portion and a second guide portion for guiding said process cartridge, said process cartridge including: a cartridge frame;   an electro-photographic photosensitive drum;   a charge roller for charging said electro-photographic photosensitive drum;   a development roller for developing a latent image formed on said electro-photographic photosensitive drum, rotating to convey toner to said electrophotographic photosensitive drum;   a cleaning blade in contact with said electro-photographic photosensitive drum to remove toner remaining on said electro-photographic photosensitive drum;   a first cylindrical projection, which projects outwardly from one of opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum;   a second cylindrical projection, which projects outwardly from the other of the opposite ends of said cartridge frame, and coaxially with said electro-photographic photosensitive drum;   a drum gear, which is provided at one axial end of said electrophotographic photosensitive drum, and which meshes with a driving gear provided on a main assembly of said electro-photographic image forming apparatus to receive a driving force for rotating said electro-photographic photosensitive drum when said process cartridge is mounted to the main assembly of the electro-photographic image forming apparatus;   a first drum shaft, which is pressed into a central portion of said first cylindrical projection, and which supports said electro-photographic photosensitive drum on said cartridge frame; and   a second drum shaft, which is pressed into a central portion of said second cylindrical projection, and which supports said electro-photographic photosensitive drum on said cartridge frame;     b. a first recess and a second recess, which engage with said first cylindrical projection and said second cylindrical projection, respectively, to fix a position of said process cartridge;   c. a transfer roller for transferring a toner image formed on said electro-photographic photosensitive drum contained in said process cartridge to the recording material;   d. a pair of rotative members for fixing on a recording material the toner image transferred onto the recording material by said transfer roller; and   e. a conveyer member for conveying the recording material by rotating; wherein said second cylindrical projection is larger than an opening of said first guide portion, thereby being prevented from being inserted into the opening of said first guide portion;   wherein a thickness of said second cylindrical projection is greater than a thickness of said first cylindrical projection;   wherein a diameter of said second cylindrical projection is larger than a diameter of said first cylindrical projection;   wherein said second drum shaft is larger in diameter than said first drum shaft; and   wherein said first guide portion and said second guide portion guide said first cylindrical projection and said second cylindrical projection, respectively.     
     
     
       28. An electro-photographic image forming apparatus according to claim 27, wherein said electro-photographic image forming apparatus is an electro-photographic copying machine, a laser beam printer, or a facsimile apparatus. 
     
     
       29. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, said process cartridge comprising: a cartridge frame;   an electrophotographic photosensitive drum;   processing means for acting on said electrophotographic photosensitive drum;   a first projection projecting outwardly from one of opposite ends of said cartridge frame, and coaxially with said electrophotographic photosensitive drum; and   a second projection projecting outwardly from the other of said opposite ends of said cartridge frame, and coaxially with said electrophotographic photosensitive drum,   wherein a dimension of said second projection measured in a direction perpendicular to a longitudinal direction of said photosensitive drum is larger than that of said first projection.   
     
     
       30. A process cartridge according to claim 29, wherein said first and second projections are cylindrical, and a diameter of said second projection is larger than that of said first projection. 
     
     
       31. A process cartridge according to claim 29, wherein a driving force receiving member is mounted at one end of said electrophotographic photosensitive drum, and wherein, when said process cartridge is mounted to the main assembly of the electrophotographic image forming apparatus, said driving force receiving member meshes with a driving force transmitting member provided in the main assembly to receive a driving force for rotating said electrophotographic photosensitive drum. 
     
     
       32. A process cartridge according to claim 31, wherein said driving force receiving member is a compound gear, a first gear portion of which meshes with the driving gear when said process cartridge is mounted to the main assembly of the electrophotographic image forming apparatus, and a second gear portion of which meshes with a transfer roller gear provided in the main assembly of the electrophotographic image forming apparatus to transmit a driving force to the transfer roller for rotating the transfer roller. 
     
     
       33. A process cartridge according to claim 29, wherein a thickness of a cylindrical wall of said second projection is greater than a thickness of a cylindrical wall of said first projection. 
     
     
       34. A process cartridge according to claim 29 or 33, wherein one end of a first drum shaft, for supporting said electrophotographic photosensitive drum, is pressed into a central portion of said first projection and one end of a second shaft, for supporting said electrophotographic photosensitive drum, is pressed into a central portion of said second projection, and wherein said second drum shaft is larger in diameter than said first drum shaft. 
     
     
       35. A process cartridge according to claim 29, wherein, when said process cartridge is mounted to the electrophotographic image forming apparatus, said first projection and said second projection are engaged with recesses provided in the main assembly to position said process cartridge, wherein the main assembly is provided with a first guide groove portion for guiding said first projection to the recess, and a second guide groove portion for guiding said second projection to the recess, and wherein an entering opening of said second guide groove portion, through which said second projection is to be put, is larger than an entering opening of said first guide groove portion, through which said first projection is to be put, thereby preventing said second projection from being put through the entering opening of the first guide portion. 
     
     
       36. A process cartridge according to claim 29, wherein said process cartridge integrally comprises said electrophotographic photosensitive drum, and at least one of a charging member, a developing member, and cleaning member, as said processing means, and is detachably mountable to the main assembly of the electrophotographic image forming apparatus.